JPH0628782Y2 - Sealed lead acid battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a sealed lead acid battery.

Conventional technology Conventional sealed lead-acid batteries absorb oxygen gas generated from the anode plate during charging with the cathode plate to produce lead oxide, which immediately reacts with the contained sulfuric acid to produce lead sulfate, and leads to lead oxide by charging. It is reduced to water and oxygen gas is recovered as water. As described above, the spongy lead, which is a reaction material of the cathode plate, plays a role of absorbing oxygen in the battery, and so-called retainer, which is a non-woven fabric of glass fiber, because oxygen gas which is a gas directly contacts with lead. Is used to create a state of lack of electrolyte, and collects oxygen gas that has passed through the space inside the retainer and diffused from outside the electrode group. The electrode plate group of this type of battery is a laminate of a cathode plate and a cathode plate of approximately the same size through a retainer, with the upper part connected to a strap,
After accommodating the electrode plate group in the battery case, the electrolytic solution is added to the extent that free water is not generated and charging is performed. In this state, the size of the retainer is as large as the inside of the battery case, and the retainer is impregnated with a large amount of electrolytic solution.
It has two characteristics.

Problems to be Solved by the Invention In the sealed lead-acid battery as described above, it has been found that there are many oxygen gas absorption areas around and above the cathode plate, and they are charged, but more than other parts. Contains a lot of lead sulfate.
However, a major problem of the sealed lead-acid battery is a change in the specific gravity of the electrolyte above and below the electrode plate, in other words, a stratification phenomenon. This is a phenomenon in which the specific gravity of the lower part of the electrode plate group becomes high due to charging and discharging, which leads to deterioration of battery performance. As described above, there is a problem that the battery characteristics are significantly deteriorated due to the special structure for sealing.

Means for Solving the Problems In view of the above points, the present invention provides an electrode plate group in which an anode plate and a cathode plate are stacked via a retainer holding an electrolytic solution, and A sealed lead-acid battery housed in a battery case so as to be parallel to the bottom surface of the battery case, wherein the lower ends of the anode plate and the retainer in the lower part of the electrode plate group are located above the lower end of the cathode plate. A space is formed between the cathode and the bottom of the battery case, and the lower part of the cathode plate is exposed in the space by 5 to 15% of the height of the cathode plate. .

As described above, the oxygen gas is largely absorbed where the cathode plate is exposed.Therefore, there are many exposed parts of the cathode plate in the lower part of the electrode plate group. Is recovered as water. This means that for the stratification of the electrolytic solution, water is added to the place where the specific gravity of the electrolytic solution at the lower part of the cathode plate is high, and the normal stratification phenomenon is that lead sulfate is added to the lower end of the cathode plate. It accumulates, but its amount is small, and it is fully charged even if a large amount of gas absorption occurs.

Action Suppresses stratification of the electrolyte due to charge and discharge.

Example A 6-volt 6-ampere-hour sealed lead-acid battery was used as a test battery. This is shown in the drawing. The electrode plate group 1 is composed of an anode plate 2, a retainer 3 and a cathode plate 4, and is housed in a battery case 5. The retainer 3 is separated at the lower end, and the lower part of the cathode plate 4 is longer than the anode plate 2 by 10% or more, and is exposed to the bottom of the battery case 5. When the battery is charged, the oxygen gas generated from the anode plate 2 concentrates on the cathode plate 4 through the space 6 provided in the lower portion of the battery case, and at the lower portion of the cathode plate 4 due to the reaction of the oxygen cycle already described. Moisture is recovered. On the other hand, by repeating charge and discharge, stratification progresses and the concentration of the electrolytic solution in the lower part of the electrode plate group 1 shown in the drawing increases,
Due to the recovered water, the increase in the concentration will be suppressed. As this state progresses, the amount of liquid in the lower part of the electrode plate group 1 increases, but due to the capillary action of the retainer 3, the quantitative distribution of the electrolytic solution in the height direction does not change significantly. In addition, various studies were conducted on the exposed area of the cathode plate 4, and 10% of the height of the cathode plate 4 was optimal, and the gas absorption amount was insufficient at 5% or less, and the gas absorption reaction became large at 15% or more and lead It became difficult to give back.

Effect of the Invention As described above, the present invention determines the height of the cathode plate in the electrode plate group.
Since it was exposed at the bottom of the cathode plate by about 10%, it is of great practical value, such as suppressing the stratification phenomenon of the sealed lead-acid battery.

[Brief description of drawings]

 The drawing is an illustration of the sealed lead-acid battery of the present invention. 1 is an electrode plate group, 4 is a cathode plate.

Claims (1)

[Scope of utility model registration request] 1. A battery case in which an electrode plate group in which an anode plate and a cathode plate are stacked via a retainer holding an electrolytic solution is arranged so that the stacking direction of the electrode plate group is parallel to the bottom surface of the battery case. In the sealed lead-acid battery housed in, the lower end of the anode plate and the retainer in the lower part of the electrode plate group is located above the lower end of the cathode plate to form a space between the bottom surface of the battery case. The lower part of the cathode plate is exposed in the space by 5 to 15% of the height of the cathode plate.
A sealed lead acid battery characterized by the above.